Congenic mice confirm the presence of linked loci on chromosome 7 that influence early progenitor cell number.

Numbers of eHPCs (A) and HSCs (B) per femur in heterozygous congenic animals (B6.DBA chr.7 [0-37, 42-50 cM]/B6, DBA.B6 chr.7 [0-18, 23-50 cM]/DBA) are shown (see “Materials and methods”). The inbreeding coefficient for each line is 0.95; the remaining 5% donor genomic background was different in each animal and did not include any other mapped linked loci. The combined inbreeding coefficient for both congenic lines is 0.9975. P < .05 for numbers of eHPCs per femur for B6 versus B6.DBA, DBA versus DBA.B6, and B6.DBA versus DBA.B6; n = 10 for C57BL/6, n = 7 for DBA/2, n = 4 for B6.DBA, n = 6 for DBA.B6 eHPCs, and n = 1 for DBA.B6 HSCs. Mean values ± 1 SEM are shown.